Conventionally, there are a number of schemes available for monitoring water level of a water body (e.g., a river, a lake, etc.), in order to gain awareness of potential flooding in advance. For example, a commercially available water gauge may be placed directly in the water body to detect the water level. Alternatively, human observers may observe the water level in person or observe satellite images acquired by a satellite.
There are some drawbacks associated with the conventional schemes for monitoring the water level. For example, the water gauge has the risk of being flushed away by flooding, and may not be controllable afterward. Using human observers may be costly, and the observed result may not be objective. Using the satellite image may have accuracy issues due to the large area covered by the satellite image.